✍ The little lisper

"There are surprises in store for the diligent reader of this masterful
introduction to recursion as a fundamental tool for expressing and solving
problems. With wit and wisdom, The Little LISPer unfolds some of the most
beautiful concepts in mathematics, computer science, and logic.
The authors' goal is to show that recursive thinking is first of all fun, that
it is powerful, and that the programming language Lisp allows one to express
ideas recursively and naturally. There are hard problems along the way, but
their solution brings mastery of recursive, functional, and meta-linguistic
abstractions, developing skills in the underlying creative programming in
Lisp. The Little LISPer is self-contained: an interpreter for the language is
developed using the tools of the book itself."